1. Field of the Invention
The instant invention relates to devices for assisting infirm or injured individuals to move from a standing position to a sitting position and from a sitting position to a standing position. More particularly, the instant invention is directed to improvements chairs and toilet seats which are configured to assist infirm individuals in lowering themselves to and raising themselves from the sitting position.
2. Prior Art
The patent literature includes numerous arrangements for assisting infirm individuals in sitting down and standing up from a chair or toilet seat.
U.S. Pat. No. 4,538,853 discloses a chair with a resilient mechanism for assisting an occupant in raising him- or herself to a standing position. The chair is provided with a seat cushion which pivots relative to the chair frame about an axis near the rearward edge of the frame. The movement also serves to at least simultaneously partially elevate an armrest. When the chair is occupied, resilient struts are compressed to store energy for lifting the occupant. The seat may be manually locked in its lowered position.
U.S. Pat. No. 3,975,051 discloses an orthopedic chair which includes a movably supported frame assembly which serves to maintain a forwardly and downwardly extending saddle-shaped seat at a desired elevation between a pair of laterally spaced sidewalls and a backrest. The chair of this patent utilizes footrests and relies on electricity for its operation.
U.S. Pat. No. 3,473,174 discloses a power-driven, tilted seat in which the seat and associated armrests are fixed relative to one another and move with respect to a supporting frame. Power-actuated hydraulic cylinders are used to raise and lower the seat. U.S. Pat. No. 4,587,678 to Love also relies on an electrically driven hydraulic lift. However, in this patent, the armrests are fixed with respect to the frame, and only the seat moves.
U.S. Pat. No. 4,907,303 discloses an orthopedic chair with a spring-loaded seat, wherein a coil spring is tensioned as a user sits in the seat in order to store energy where it is subsequently used to assist in lifting the user to his or her feet when he or she wishes to stand. A hand brake grips a cable attached to the spring to control application of the spring's force to the seat.
Each of the above-discussed patents are exemplary of prior art approaches to the problem of providing chairs and seats for the infirm. However, none of these seats discloses arrangements wherein a seat not requiring auxiliary power functions effectively for people over a wide range of heights and weights while effectively utilizing ergonomic principles in its design and operation to provide convenience, comfort, and security for its users.